libobjc/objc-private/module-abi-8.h

   1 /* Definitions of Module Structures used by ABI version 8
   2    Copyright (C) 1993, 1995, 1996, 1997, 2001, 2002, 2003, 2004, 2005,
   3    2007, 2009, 2010 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under the
   8 terms of the GNU General Public License as published by the Free Software
   9 Foundation; either version 3, or (at your option) any later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13 FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  14 details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #ifndef __objc_private_module_abi_8_INCLUDE_GNU
  26 #define __objc_private_module_abi_8_INCLUDE_GNU
  27
  28 /* For every class which happens to have statically allocated instances in
  29    this module, one OBJC_STATIC_INSTANCES is allocated by the compiler.
  30    INSTANCES is NULL terminated and points to all statically allocated
  31    instances of this class.  */
  32 struct objc_static_instances
  33 {
  34   char *class_name;
  35 #ifdef __cplusplus
  36   id instances[1];
  37 #else
  38   id instances[0];
  39 #endif
  40 };
  41
  42 /* Whereas a Module (defined further down) is the root (typically) of a file,
  43    a Symtab is the root of the class and category definitions within the
  44    module.
  45
  46    A Symtab contains a variable length array of pointers to classes and
  47    categories  defined in the module.   */
  48 struct objc_symtab
  49 {
  50   unsigned long sel_ref_cnt;  /* Unused (always set to 0). */
  51   SEL      refs;              /* The table of selectors referenced in
  52                                  this module.  This is terminated by a
  53                                  selector with NULL sel_id and NULL
  54                                  sel_types.  */
  55   unsigned short cls_def_cnt; /* Number of classes compiled (defined)
  56                                  in the module. */
  57   unsigned short cat_def_cnt; /* Number of categories compiled
  58                                  (defined) in the module. */
  59   void      *defs[1];         /* Variable array of pointers.
  60                                  cls_def_cnt of type Class followed by
  61                                  cat_def_cnt of type Category_t,
  62                                  followed by a NULL terminated array
  63                                  of objc_static_instances. */
  64 };
  65
  66 /* The compiler generates one of these structures for each module that
  67    composes the executable (eg main.m).
  68
  69    This data structure is the root of the definition tree for the
  70    module.
  71
  72    A collect program runs between ld stages and creates a ObjC ctor
  73    array.  That array holds a pointer to each module structure of the
  74    executable.  */
  75 struct objc_module
  76 {
  77   unsigned long version;      /* Version of the Module data
  78                                  structure.  */
  79   unsigned long size;         /* sizeof(Module) according to the
  80                                  compiler - only used to sanity check
  81                                  that it matches sizeof(Module)
  82                                  according to the runtime.  */
  83   const char* name;           /* Name of the file used to compile the
  84                                  module - not set by modern compilers
  85                                  for security reasons.  */
  86   struct objc_symtab *symtab; /* Pointer to the Symtab of the module.
  87                                  The Symtab holds an array of pointers
  88                                  to the classes and categories defined
  89                                  in the module. */
  90 };
  91
  92 /* The compiler generates one of these structures for a class that has
  93    instance variables defined in its specification.  */
  94 struct objc_ivar
  95 {
  96   const char* ivar_name;  /* Name of the instance variable as entered
  97                              in the class definition. */
  98   const char* ivar_type;  /* Description of the Ivar's type.  Useful
  99                              for debuggers. */
 100   int        ivar_offset; /* Byte offset from the base address of the
 101                              instance structure to the variable. */
 102 };
 103
 104 struct objc_ivar_list
 105 {
 106   int   ivar_count;              /* Number of structures (Ivar)
 107                                     contained in the list.  One
 108                                     structure per instance variable
 109                                     defined in the class. */
 110   struct objc_ivar ivar_list[1]; /* Variable length structure. */
 111 };
 112
 113 /* The compiler generates one (or more) of these structures for a
 114    class that has methods defined in its specification.
 115
 116    The implementation of a class can be broken into separate pieces in
 117    a file and categories can break them across modules. To handle this
 118    problem is a singly linked list of methods.  */
 119 struct objc_method
 120 {
 121   SEL         method_name;  /* This variable is the method's name.
 122                                The compiler puts a char* here, and
 123                                it's replaced by a real SEL at runtime
 124                                when the method is registered.  */
 125   const char* method_types; /* Description of the method's parameter
 126                                list.  Used when registering the
 127                                selector with the runtime.  When that
 128                                happens, method_name will contain the
 129                                method's parameter list.  */
 130   IMP         method_imp;   /* Address of the method in the
 131                                executable. */
 132 };
 133
 134 struct objc_method_list
 135 {
 136   struct objc_method_list*  method_next; /* This variable is used to
 137                                             link a method list to
 138                                             another.  It is a singly
 139                                             linked list. */
 140   int            method_count;            /* Number of methods defined
 141                                              in this structure. */
 142   struct objc_method method_list[1];      /* Variable length
 143                                              structure. */
 144 };
 145
 146 /* Currently defined in Protocol.m (that definition should go away
 147    once we include this file).  Note that a 'struct
 148    objc_method_description' as embedded inside a Protocol uses the
 149    same trick as a 'struct objc_method': the method_name is a 'char *'
 150    according to the compiler, who puts the method name as a string in
 151    there.  At runtime, the selectors need to be registered, and the
 152    method_name then becomes a SEL.  */
 153 struct objc_method_description_list
 154 {
 155   int count;
 156   struct objc_method_description list[1];
 157 };
 158
 159 /* Currently defined by objc/objc.h.  */
 160 /*
 161 struct objc_protocol {
 162   struct objc_class* class_pointer;
 163   char *protocol_name;
 164   struct objc_protocol_list *protocol_list;
 165   struct objc_method_description_list *instance_methods, *class_methods;
 166 };
 167 */
 168
 169 struct objc_protocol_list
 170 {
 171   struct objc_protocol_list *next;
 172   size_t count;
 173   Protocol *list[1];
 174 };
 175
 176 /*
 177   The compiler generates one of these structures for each class.
 178
 179   This structure is the definition for classes.
 180
 181   This structure is generated by the compiler in the executable and
 182   used by the run-time during normal messaging operations.  Therefore
 183   some members change type. The compiler generates "char* const" and
 184   places a string in the following member variables: super_class.
 185 */
 186 #ifndef __objc_STRUCT_OBJC_CLASS_defined
 187 struct objc_class {
 188   struct objc_class*  class_pointer;    /* Pointer to the class's meta
 189                                            class. */
 190   struct objc_class*  super_class;      /* Pointer to the super
 191                                            class. NULL for class
 192                                            Object. */
 193   const char*         name;             /* Name of the class. */
 194   long                version;          /* Unknown. */
 195   unsigned long       info;             /* Bit mask.  See class masks
 196                                            defined below. */
 197   long                instance_size;    /* Size in bytes of the class.
 198                                            The sum of the class
 199                                            definition and all super
 200                                            class definitions. */
 201 #ifdef _WIN64
 202   /* We pad the structure manually to prevent warning when -Wpadded is
 203      used.  The compiler automatically pads the structures that it
 204      generates, so this manually padded structure still matches the
 205      one generated by the compiler, but if we don't pad manually,
 206      -Wpadded detects that padding is being added and generates
 207      annoying warnings.  This hack is necessary as on LLP64 targets
 208      sizeof (long) isn't equal to sizeof (void *).  */
 209   long pad;
 210 #endif
 211   struct objc_ivar_list* ivars;         /* Pointer to a structure that
 212                                            describes the instance
 213                                            variables in the class
 214                                            definition.  NULL indicates
 215                                            no instance variables.
 216                                            Does not include super
 217                                            class variables. */
 218   struct objc_method_list*  methods;    /* Linked list of instance
 219                                            methods defined for the
 220                                            class. */
 221   struct sarray *    dtable;            /* Pointer to instance method
 222                                            dispatch table. */
 223   struct objc_class* subclass_list;     /* Subclasses */
 224   struct objc_class* sibling_class;
 225
 226   struct objc_protocol_list *protocols; /* Protocols conformed to */
 227   void* gc_object_type;
 228 };
 229 #endif /* __objc_STRUCT_OBJC_CLASS_defined */
 230
 231 /* This is used to assure consistent access to the info field of
 232    classes.  */
 233 #ifndef HOST_BITS_PER_LONG
 234 # define HOST_BITS_PER_LONG  (sizeof(long)*8)
 235 #endif
 236
 237 #define __CLS_INFO(cls) ((cls)->info)
 238 #define __CLS_ISINFO(cls, mask) ((__CLS_INFO(cls)&mask)==mask)
 239 #define __CLS_SETINFO(cls, mask) (__CLS_INFO(cls) |= mask)
 240 #define __CLS_SETNOTINFO(cls, mask) (__CLS_INFO(cls) &= ~mask)
 241
 242 /* The structure is of type MetaClass */
 243 #define _CLS_META 0x2L
 244 #define CLS_ISMETA(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_META))
 245
 246 /* The structure is of type Class */
 247 #define _CLS_CLASS 0x1L
 248 #define CLS_ISCLASS(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_CLASS))
 249
 250 /* The class is initialized within the runtime.  This means that it
 251    has had correct super and sublinks assigned.  */
 252 #define _CLS_RESOLV 0x8L
 253 #define CLS_ISRESOLV(cls) __CLS_ISINFO(cls, _CLS_RESOLV)
 254 #define CLS_SETRESOLV(cls) __CLS_SETINFO(cls, _CLS_RESOLV)
 255
 256 /* The class has been send a +initialize message or a such is not
 257    defined for this class.  */
 258 #define _CLS_INITIALIZED 0x04L
 259 #define CLS_ISINITIALIZED(cls) __CLS_ISINFO(cls, _CLS_INITIALIZED)
 260 #define CLS_SETINITIALIZED(cls) __CLS_SETINFO(cls, _CLS_INITIALIZED)
 261
 262 /* The class is being constructed; it has been allocated using
 263    objc_allocateClassPair(), but has not been registered yet by using
 264    objc_registerClassPair().  This means it is possible to freely add
 265    instance variables to the class, but it can't be used for anything
 266    yet.  */
 267 #define _CLS_IN_CONSTRUCTION 0x10L
 268 #define CLS_IS_IN_CONSTRUCTION(cls) __CLS_ISINFO(cls, _CLS_IN_CONSTRUCTION)
 269 #define CLS_SET_IN_CONSTRUCTION(cls) __CLS_SETINFO(cls, _CLS_IN_CONSTRUCTION)
 270 #define CLS_SET_NOT_IN_CONSTRUCTION(cls) __CLS_SETNOTINFO(cls, _CLS_IN_CONSTRUCTION)
 271
 272 /* The class number of this class.  This must be the same for both the
 273    class and its meta class object.  */
 274 #define CLS_GETNUMBER(cls) (__CLS_INFO(cls) >> (HOST_BITS_PER_LONG/2))
 275 #define CLS_SETNUMBER(cls, num) \
 276   ({ (cls)->info <<= (HOST_BITS_PER_LONG/2); \
 277      (cls)->info >>= (HOST_BITS_PER_LONG/2); \
 278      __CLS_SETINFO(cls, (((unsigned long)num) << (HOST_BITS_PER_LONG/2))); })
 279
 280
 281 /* The compiler generates one of these structures for each category.
 282    A class may have many categories and contain both instance and
 283    factory methods.  */
 284 struct objc_category
 285 {
 286   const char*   category_name;                /* Name of the category.
 287                                                  Name contained in the
 288                                                  () of the category
 289                                                  definition.  */
 290   const char*   class_name;                   /* Name of the class to
 291                                                  which the category
 292                                                  belongs.  */
 293   struct objc_method_list  *instance_methods; /* Linked list of
 294                                                  instance methods
 295                                                  defined in the
 296                                                  category. NULL
 297                                                  indicates no instance
 298                                                  methods defined.  */
 299   struct objc_method_list *class_methods;     /* Linked list of
 300                                                  factory methods
 301                                                  defined in the
 302                                                  category.  NULL
 303                                                  indicates no class
 304                                                  methods defined.  */
 305   struct objc_protocol_list *protocols;       /* List of Protocols
 306                                                  conformed to.  */
 307 };
 308
 309 #endif /* __objc_private_module_abi_8_INCLUDE_GNU */